# CVE-2026-92543: Docker Engine insecure-registry fallback via malicious DNS responses

CVE-2026-92543 is fixed in 3 products on 1 platform, first by ALAS2023-2026-3266, released November 7, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-92543
- Priority: High
- CVSS: n/a (Important)
- EPSS: 0.0009
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 11, 2026
- Weakness: Improper Certificate Validation
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-92543

## Description

Docker Engine classifies a registry hostname as insecure using an any-match DNS check. loadInsecureRegistries() injects 127.0.0.0/8 and ::1/128 as insecure CIDRs by default. isCIDRMatch resolves all of the hostname's addresses and returns true if a single address is in the insecure CIDR list. Because the transport re-dials the hostname rather than the CIDR-matching address, a DNS answer set of one loopback IP plus a non-loopback attacker IP disables certificate verification and enables HTTP fallback for the registry connection.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | docker amzn 2023 | 25.0.18-1.amzn2023.0.1 | [ALAS2023-2026-3266](https://patchblox.com/security/data/fix/linux/alas2023-2026-3266.md) | Nov 7, 2026 |
| Linux | docker-debuginfo amzn 2023 | 25.0.18-1.amzn2023.0.1 | [ALAS2023-2026-3266](https://patchblox.com/security/data/fix/linux/alas2023-2026-3266.md) | Nov 7, 2026 |
| Linux | docker-debugsource amzn 2023 | 25.0.18-1.amzn2023.0.1 | [ALAS2023-2026-3266](https://patchblox.com/security/data/fix/linux/alas2023-2026-3266.md) | Nov 7, 2026 |

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Data as of 2026-11-11T13:47:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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